AIDS-005403 AIDS005403 Penicillin Et(NH)2 dimer [2R-[2.alpha.(R*),4.-beta.-]]-4,4'-[1,2-Ethanediylbis[aminocarbonyl]]bis[5,5-dimethyl-.alpha.-[[[(1,1'-biphenyl)-2-yl]carbonyl]amino]-N-[(1,1-dimethylethoxy)carbonylmethyl]-2-thiazolidineacetamide]